Cooling servers, cleaning bodies: recycled heat from server room provides hot water in the sports hall showers of the Jean Moulin University, Lyon

Type of organisation or company
Language for original content
Project elaborated in partnership
Submitted by
Institut de l'économie circulaire
Start/End date
Type of funding

Stimergy made two crucial observations: Firstly that 45% of energy needs of servers came from their cooling systems. Secondly that water heating was one of the main sources of energy consumption in public and residential buildings.

By using a liquid cooling and heat recovery system in server rooms or by decentralising its servers in "digital boilers" located in residential and public buildings, Stimergy "kills two birds with one stone" by recycling heat from data servers to water heating systems.

From the economic side, the server room technology improves the energy performance of the rooms therefore cutting operational costs. The costs of the decentralized option on the other hand are compensated by not needing to bear the costs of the cooling systems that server rooms require to operate.

From the environmental side, the gain is even clearer. Neither, the energy that would have been used for the cooling system of the servers nor the energy that is saved by using the heat provided by Stimergy's "digital boilers" and server rooms is expended. This therefore greatly reduces the energetic consumption and therefore environmental impact of the servers and water heating systems.

Main results

Some solutions put forward by Stimergy:

  • One 1 kW digital boiler in Grenoble: housing association (OPAC38)
  • One 1 kW digital boiler in Lyon: Jean Moulin University
  • Two 4 kW digital boiler in Grenoble: student hall of residence (Nexity) and housing association (OPAC38)
  • Two 4 kW digital boilers in Nantes: apartment building (Nantes Metropole Habitat)
  • Six 8 kW digital boilers in Paris: Swimming pool in the Butte-aux-Cailles (Mairie de Paris)
  • One 8 kW digital boiler in Paris: housing association (RIVP)
  • One 8 kW digital boiler in Paris: housing association (Logement Franciliens)
  • One 8 kW digital boiler in Paris: student hall of residence (groupe CARDINAL)
  • One user of the digital backup capabilities – Chambery (MND)
  • One user of computing capabilities – Paris (Teamto).